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Unformatted text preview: III emission (and thus of a combination of optical depth and velocity shear). Finally, recall the use of emission lines as kinematic tracers . Thermal motions produce minimal linewidths for a given ion, with a distribution function of line-of-sight velocity This is small for atoms, and smallest for heavier ones. At 10 4 K, the 1/e width is 12 km/s for hydrogen and only 4.5 km/s for oxygen. Thus all the structure and widths seen in AGN spectra are from mass motions or some scattering process that can smear frequencies very strongly (a role for electron scattering has been found in a few cases)....
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This note was uploaded on 11/10/2011 for the course AST AST1002 taught by Professor Emilyhoward during the Fall '10 term at Broward College.
- Fall '10